It is known that the physicochemical properties of solids in particulate form are influenced by the size and shape of the particles. As particle size of solids diminishes in scale, there is an enhancement of properties, and often the inception of new properties. Investigators are finding that nanostructural materials can exhibit unique mechanical, electronic and optical properties.
New commercial products are becoming available which provide special advantage because of fine particle size. Zinc oxide is widely utilized as an ingredient in human health products. Superior results are now obtained by the use of submicron transparent zinc oxide powder. The ultrafine zinc oxide provides advantage for UVA/B-protection in cosmetic formulations, and exhibits enhanced antimicrobial capacity and functions as a preservative.
Alkali metal bicarbonate is another commodity reagent which has found application in a broad variety of products such as laundry detergents, deodorizers, creams and lotions, dentifrices, antacids, buffers, fungicides, and the like.
There is evidence that fine particle size alkali metal bicarbonate can exhibit increased reactivity in comparison with coarse grain alkali metal bicarbonate. In soda cracker production, finely divided sodium bicarbonate ingredient is more efficiently distributed and effectively reactive during the cracker dough preparation. The finished baked cracker is an improved product which has a substantially uniform texture, flavor and surface color, and a consistent pH throughout.
There is continuing interest in the development of reagents such as alkali metal bicarbonate which have an ultrafine particle size, and exhibit a novel combination of properties when utilized as an ingredient in personal care, biologically active, household, and specialty type products.
Accordingly, it is an object of this invention to provide particulate alkali metal bicarbonate having an ultrafine particle size, and a surface area of at least about four square meters per gram.
It is another object of this invention to provide alkali metal bicarbonate powder having a submicron particle size, and exhibiting transparency in the visible light range.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.
Publications of background interest with respect to the present invention subject matter include U.S. Pat. Nos. 2,378,147; 3,241,977; 4,997,454; and 5,147,631.